Resistive memories use a memory element that can change the electrical resistance through suitable programming. Possible representatives are, for instance, MRAM, phase change RAM or conductive bridging ram (CBRAM). In this case, the resistance ratio between the two switching states may amount to a few 10%, such as in the case of MRAM for instance, or many orders of magnitude, such as in the case of CBRAM, which is discussed in detail below by way of example. In the OFF state, a CB contact (CBJ, conductive bridging junction) has a resistance of 1010 . . . 1011 Ω, which is of the same order to magnitude as the OFF state of a FET that is typically used as a switching element is semiconductor circuits. The consequence of the extreme high-resistance nature of the CBJ is that turned-off nodes between a CBJ and a selection transistor are practically totally electrically isolated and are thus very sensitive to interference voltages. At the same time, by way of example, a CB contact can be changed over from the high-resistance state to the low-resistance state by the application of a voltage, that is to say that this may also occur unintentionally as a result of the occurrence of interference voltages.
Capacitive coupling effects are dominant at electrically isolated nodes. The ratio of the parasitic capacitances of the switching element and the surrounding circuit determines the magnitude of the interference voltages that occur. A specific charge Q is involved in the case of such capacitive coupling in of interference voltages. In accordance with the capacitor equation C equals Q/U, the voltage U that results when a capacitance C is charged with a constant quantity of charge is proportional to the reciprocal of the capacitance C. The greater the capacitance, the lower the voltage U occurring across the capacitance C. In order that interference voltages coupled in capacitively are kept as small as possible, it is accordingly desirable to increase the capacitance of the switching element in the memory cell.